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Blender 2.68: Cycles

Performance

Official Blender on Windows has become significantly faster, getting closer to performance on Linux and Mac OS X. Especially scenes with much geometry will benefit from the optimization, rendering often 30% faster. Linux and Mac OS X also benefit but more on the order of 10%.

Render Passes

Mist pass

Mist pass support was added, with start, depth and falloff control. This pass can be used in compositing to add fade out object that are further away, for example as a factor input for a Mix RGB node. If the pass is enabled in a render layer a Mist Pass panel will be shown in the world properties. (r57278)

Ray Visibility

Ray visibility is now supported for all light sources: lamps, emitting meshes and the world environment. Using these options it's possible to let light from these sources only selectively affect diffuse, glossy or transmission shaders.